Condensing by a condensing optical system a laser light output from a laser light source and irradiating the laser light to a processing object allows processing the processing object. If by simply condensing laser light by use of a lens, scanning laser light to one condensing position allows processing a processing object into a desired shape. However, the time required for processing is long in this case.
The simplest method for shortening the processing time is to perform multi-point simultaneous processing by simultaneously condensing and irradiating laser light to a plurality of condensing positions. For example, using a plurality of laser light sources and condensing laser lights output from the respective laser light sources by a lens allows performing multi-point simultaneous processing. However, in this case, a plurality of laser light sources are used, which thus results in a high cost and a complicated installation area and optical system.
An invention that intends to solve such problems has been disclosed in Patent Literature 1. In this invention disclosed in Patent Literature 1, a hologram is presented on a phase modulating spatial light modulator, a laser light output from one laser light source is phase-modulated by the spatial light modulator, and the phase-modulated laser light is simultaneously condensed and irradiated to a plurality of positions by a condensing optical system. The hologram presented on the spatial light modulator has such a phase modulation distribution that laser light is condensed to a plurality of condensing positions by a condensing optical system.